Storage of large volumes of granular materials, including agricultural products such as wheat, corn or barley can benefit from the use of temporary structures. Agricultural endeavors in particular, due to vagaries in the size and timing of harvested crops, market conditions and weather, can benefit from storage facilities which protect crops while allowing easy filling of the structure using conventional handling equipment and permitting portions of the harvested crops to be easily withdrawn on variable schedules. Due to the highly variable nature of the factors which produce the need for storage, it can be very inefficient to build permanent structures large enough to contain the largest possible crop for the maximum time period desired.
In addition to being cost effective to erect and maintain, it is desirable for temporary structures for agricultural products to allow the crops stored therein to be ventilated by air circulation to permit drying to optimal levels to maximize the market price of the crops and to prevent rot.
Grains are often stored in permanent, fixed structures such as silos and similar metal or wood structures. Such structures are, by their nature, fixed and somewhat costly to erect. It is known to provide temporary storage facilities of the general type herein described, which are cost-effective to prepare and utilize, may be easily dismantled and transported, which at the same time providing effective temporary storage during a typical harvest season.
Temporary storage facilities of the type herein described utilize a base, a retaining wall, a ventilating system, and a cover.
A base for temporary storage facilities is typically a prepared surface, often circular, oval or rectangular. The surface may be an inert aggregate material or an asphalt material.
The retaining wall is typically constructed of several perforated wall panels, the perforations being numerous and uniform in size, and having a dimension smaller than the typical dimension of the agricultural grain to be stored within the perimeter formed by the retaining wall. The retaining wall sections are supported at an angle in relation to vertical, and provided with the necessary reinforcement to carry the loads imposed by the material being stored within the facility. Typically, the retaining wall sections are connected in an end to end fashion providing a substantially contiguous barrier surrounding the perimeter of the storage surface.
To retard spoilage and protect the stored product, the typical temporary storage facility of the type herein described requires positive ventilation. This is accomplished by placement of numerous perforated conduits on the storage surface. Such conduits are typically sealed at one end, perforated both longitudinally and circumferentially, routed through openings formed in the retaining walls, and then connected to one or more blowers which draw air from the ventilating conduits. This action lowers the pressure in the grain pile, thereby drawing air from the perimeter of the storage structure, through the retaining walls, and into the base of the grain pile. The typical covering for the temporary storage facility of the type described herein is sometimes a flexible material in the form of a sturdy but lightweight plastic film. In other installations, the cover is formed from a plurality of wedge-shaped plastic elements which are secured together to form a conical top enclosure for the grain pile.
Principal drawbacks of the present systems include the complexity and costs associated with the formation of perforated panels for the wall sections, the need to consider the dimensions of the perforations in relation to the grain being stored, and the susceptibility of the perforated panels to clogging. Attempts have been made to utilize screens as a portion of the wall panels, but both heavily perforated sheets and screens lack the rigidity required to support the loads imposed by the grain being stored in a facility.
The present invention addresses these limitations by providing a rigid support panel which is simple and inexpensive to manufacture, and which optimizes the flow of ventilating air through the supporting wall. Panels constructed according to the present invention are inherently strong by virtue of their cross-sectional shape, requiring fewer structural supports for maintaining the wall sections in the desired position, i.e., retaining the loads imposed by the material being contained.